An `alpha` particle and a proton are moving in the plane of a paper in a region where there is uniform, magnetic field directed normal to the plane. If two particels have equal linear momenta, what will be the ratio of the radii of their trajectories in the field ?

Explanation

The magnetic force acts as the centripetal force in the circular orbit i.e.,
`Bqv=(mv^(2))/(r) or, r= (mv)/(Bq)`
For the same linear momentum mv, in the same magnetic field,
`r prop (1)/(q) :. (r_(1))/(r_(2))=(e)/(2e)=(1)/(2)`